Thunderbird 78 comes with a completely revamped OpenPGP integration. Several features get implemented over the course of time, but might need manual configuration. In this article, I show you how to avoid encrypting your outgoing e-mail subjects via OpenPGP, resulting in “…” in the message overview, which can make it also hard to search for message subjects.
Thunderbird 78: Do not encrypt subject
How to disable encrypting your outgoing e-mail subjects via OpenPGP in Thunderbird 78